(1) Field of the Invention
This invention relates to an improved catalyst component for the polymerization of olefins and a catalyst therefor which are capable of providing high polymerization activity per unit weight of the catalyst component and high yield of stereoregular polymer when applied to the polymerization of olefins, and more particularly relates to a catalyst component obtained by contacting a fatty acid salt of magnesium and dialkoxymagnesium, mono or diester of an aromatic dicarboxylic acid, a halogenated hydrocarbon and a titanium halide, and to a catalyst therefor comprising the catalyst component, a silicon compound and an organoaluminium compound, where polymerization includes homopolymerization and copolymerization thereof.
(2) Description of the Prior Art
A catalyst for the polymerization of olefins formed by combining a solid titanium halide as a catalyst component with an organoaluminium compound is well known in the art. However, in the polymerization of olefins by use of the conventional catalyst, the yield of polymer per unit weight of the catalyst component or of titanium moiety in the catalyst component (hereinafter referred to simply as a polymerization activity per unit weight of the catalyst component or of titanium) is so low that the so-called deashing process for subsequently removing catalyst residues from the produced polymer is indispensable in order to obtain an industrially applicable polymer. In the deashing process, alcohols or chelating agents are used in large amounts, so that the deashing process needs an apparatus for recovery thereof as well as the deashing apparatus itself, and consequently has many problems accompanying therewith relative to resources, energy, and the like. Thus, the deashing process raises great problems to be solved urgently in the art. A number of studies and suggestions have been made for enhancing the polymerization activity per unit weight of titanium in the catalyst component, so that the complicated deashing process may be dispensed with.
Especially as a recent tendency, a large number of suggestions have been made such that the polymerization activity per unit weight of titanium in the catalyst component is remarkably enhanced in the polymerization of olefins with a catalyst component prepared by supporting a transition-metal compound as an active ingredient such as a titanium halide on a carrier material so that the active ingredient may act effectively.
However, the prior art employing magnesium chloride as the carrier as described above, has such a disadvantage that the chlorine moiety contained in the magnesium chloride conventionally used as the carrier has an adverse effect on the produced polymer, resulting in leaving problems to be solved such as requirements for such a high activity as to be substantially free from the adverse effect due to the chlorine moiety, or as requirements for controlling a concentration of the magnesium chloride itself at a sufficiently low level.
It was substantially impossible for the so-called highly active supported catalyst formed by use of a catalyst component employing the aforementioned magnesium chloride as a carrier to be of practical use, because use of the supported catalyst results in abrupt deactivation thereof in spite of high activity thereof in the beginning of polymerization, and results in raising problems in process operations, particularly in the case where a prolonged polymerization time is required as in block copolymerization and the like. In order to solve the aforementioned problems, Japanese patent laid-open publication No. 94590/1979 discloses a catalyst for the polymerization of olefins which comprises a catalyst component prepared by use of magnesium dihalide as one of the starting materials, an organoaluminium compound, an aromatic carboxylic acid ester, and a compound having a M--O--R group. However, the catalyst disclosed as above fails to solve the problem of deodorizing from the produced polymer in that organic carboxylic acid esters are used on polymerization, and requires complicated procedures for the preparation thereof with practically insufficient catalyst performance and polymerization activity with time.